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Biomedical subjects

B D Perry

Publications and source records attributed to B D Perry.

At least 37 records · Page 2Linked to original sources

Altered platelet alpha 2-adrenergic receptor binding sites in borderline personality disorder.

The authors found significantly fewer total platelet alpha 2-adrenergic receptor binding sites in 13 nonmedicated patients with borderline personality disorder than in 11 patients with borderline personality disorder who were receiving low doses of benzodiazepines and 18 nonpsychiatric control subjects. The two patient groups showed comparable degrees of depression as assessed by the Hamilton Rating Scale for Depression. However, nonmedicated borderline patients were considerably more anxious than medicated patients, raising the possibility that lower alpha 2-adrenergic receptor binding in borderline personality disorder is related to anxiety.

Anxiety Disorders

Financial analysis of East Coast fever control strategies on beef production under farm conditions.

This study provides a financial analysis of an East Coast fever immunisation trial conducted on a farm in the Coast Province of Kenya. The objective of the trial was to assess the effects of immunisation by the infection and treatment method, under different acaricidal treatments, on the productivity of beef cattle. Eighty beef cattle were immunised and an equal number acted as controls. The immunised and unimmunised groups were divided into four subgroups of 20 animals. Two subgroups, one from the immunised and one from the unimmunised group, were sprayed with acaricide twice a week; a second pair of subgroups was sprayed once every three weeks; a third pair had prolonged release acaricide-impregnated ear-tags inserted into each ear; and a fourth pair had no tick control treatment. Financial analysis revealed that the immunised subgroups were more profitable, owing to lower mortality and higher weight gains than the unimmunised subgroups. Of the immunised subgroups, the best was that sprayed with acaricide twice a week; it yielded a marginal rate of return of 244 per cent and maximised financial benefits to the farmer in this trial. However, further trials under different production circumstances would be required before the method could be recommended for widespread adoption.

Animals

Epidemiology of Potomac horse fever: an investigation into the possible role of non-equine mammals.

A serological study of antibodies to Ehrlichia risticii was carried out on 10 species of wild and domestic mammals found on or near 21 horse farms in an area of the USA in which Potomac horse fever is endemic. No antibodies were found in 133 peridomestic rodents (Norway rats and house mice), nor in 108 wild rodents (white-footed mice and meadow voles) captured on farms. Three of the six domestic animal species examined, cats, pigs and a goat, showed serological evidence of exposure to E risticii. Seropositive animals were detected on three of the 21 premises. The eight seropositive cats (of 48 cats tested) were on two farms, and the three seropositive pigs (of 14 tested) were all on one farm which lay some 3 km from where the one seropositive goat (of three tested) was found. None of the 79 dogs, 75 cattle and seven sheep tested had antibodies to E risticii. The significance of these findings is discussed in the light of current understanding of the transmission of Potomac horse fever and of the epidemiology of other related ehrlichial diseases.

Animals

A study of techniques for the distribution of oral rabies vaccine to wild raccoon populations.

This study evaluates a technique for delivering an oral rabies vaccine to wild raccoon (Procyon lotor) populations. Various baits and attractants were first tested on caged raccoons and baiting trials were then conducted in two distinct physiographic regions of Virginia (USA), the coastal plain and the Piedmont plateau. Raccoon population density studies preceded the field trials. Each polyurethane sponge bait distributed contained approximately 200 mg tetracycline as a tissue biomarker, and was presented in an outer bag with a fish-based attractant. Baits were frozen until used and distributed from an aeroplane throughout two 4-km2 sites in each region. One site received 450 baits/km2 and the other 120 baits/km2. Postbaiting evaluation included the direct observation of baits in the field and the examination of teeth and bone from trapped and hunted animals for evidence of the biomarker. Between 30% and 73% of the captured animals showed evidence of bait consumption. The proportion of animals with evidence of bait uptake changed when areas adjacent to the actual baiting site were included. The percentage of animals taking baits was not related to the density of baits that were distributed.

Administration, Oral

A baiting system suitable for the delivery of oral rabies vaccine to dog populations in Zimbabwe.

A baiting system suitable for the delivery of oral rabies vaccine to dog populations in developing countries was studied in Zimbabwe. In a field trial, 369 sponge baits containing a placebo liquid, rhodamine B as a biomarker and a pungent attractant were distributed over an area of 60 sq km in a communal land in Manicaland with a dog population of over 500. Twenty-four hours later 21 per cent of the baits were recovered and 79 per cent of these had been significantly bitten or chewed. Twenty-five per cent of the dogs examined showed evidence of superficial staining by rhodamine B indicating that they had chewed baits or ingested their contents. It was concluded that the system would deliver an oral vaccine to dog populations more efficiently than had been the case in comparable studies in wildlife populations, but that the number of baits per unit area should in future studies be increased.

Administration, Oral

Epidemiology of bovine babesiosis and anaplasmosis in Zambia.

The serological prevalence of bovine babesiosis and anaplasmosis in the traditional farming sector of six provinces of Zambia was determined using the indirect fluorescent antibody test (IFAT) for babesiosis and the card agglutination test (CAT) for anaplasmosis. Antibodies to Babesia bigemina occurred throughout the country whereas the prevalence of B. bovis followed the distribution of its tick vector Boophilus microplus which is limited to the north-eastern part of the country. Low numbers of B. bovis serologically positive cattle were demonstrated in central and southern Province. Anaplasma spp. occurred throughout Zambia but the overall percentages of positive sera were low ranging between 14.7% and 38.6% using the CAT. Two hundred sera were retested for anaplasmosis using an enzyme-linked immunosorbent assay (ELISA). Sero-prevalence rates were 1.5 to 2.3-fold greater with the ELISA than with the card agglutination test.

Agglutination Tests

The design and use of supportive epidemiologic studies.

Structured investigation of disease outbreaks or deviations from desired productivity levels do not always lead to definitive answers upon which intervention programs can be based. There is an important role for well-designed supportive epidemiologic studies to supplement outbreak investigations, and the circumstances of their use are described in this article. The design of cross-sectional, case-control, and cohort studies is also discussed, and procedures for data analysis are provided.

Animals

The distribution of African swine fever virus isolated from Ornithodoros moubata in Zambia.

African swine fever (ASF) has been reported in the Eastern Province of Zambia since 1912 and is now considered to be enzootic there. A survey of the distribution of ASF virus in Zambia was carried out by virus isolation from Ornithodoros moubata ticks collected from animal burrows in National Parks and Game Management Areas in northern, eastern, central and southern Zambia. ASF virus was isolated from ticks in all areas examined. The prevalence of infection in O. moubata was between 0.4% in South Luangwa National Park and 5.1% in Livingstone Game Park and mean infectious virus titres ranged from 10(3.4) HAD50/tick in Kakumbe Game Management Area to 10(5.9) HAD50/tick in Chunga and Nalusanga Game Management Areas. The prevalence of infection in adult ticks was between 4.7% and 5.3% in all areas examined except Sumbu National Park and Livingstone Game Park, where the prevalence was 15.1% and 13.2% respectively in adult ticks. The ratio of infected females to males for all the infected adult ticks in all areas of Zambia was 3.2:1.

African Swine Fever

Horse-baited insect trap and mobile insect sorting table used in a disease vector identification study.

A horse-baited trap and a mobile insect sorting table were used to conduct an arthropod survey for potential vectors of Potomac Horse Fever in southern Maryland and northern Virginia. The trap and table worked effectively for the live collection and sorting of haemophagous Diptera such as: Simulium spp., Stomoxys calcitrans, Musca autumnalis, Tabanus spp. and Chrysops spp. during the diurnal collections periods, and Culicoides spp. during the crepuscular periods. The trap was not as convenient for live collection of mosquito species during the nocturnal period. Modifications to the trap design was suggested for mosquito live trapping.

Animals

Rabies.

The practicing veterinarian has a key role to play in rabies control in the maintenance of protection in the companion animal populations, in the education of the pet-owning community on rabies, and in the decision-making process that accompanies human exposure to potentially rabid animals. This role encompasses far more than the routine maintenance of health and well-being in pet animal populations. Although it is important to remain diligent in the immunization of domestic pets against rabies to provide a barrier between wildlife, the main reservoir of infection, and man, it is also important to be aware of the current trends in wildlife rabies within a region. Research is currently underway to investigate methods of immunizing wildlife populations, but the effective and widespread control of rabies in these species is still a long way off; in the meantime, there will be an increasing demand for practicing veterinarians to take the lead in the control of this most fearful zoonotic disease.

Animals

Ecology and phenology of ticks in Zambia: seasonal dynamics on cattle.

A study of the seasonality and infestation rates of ticks was carried out in 11 cattle herds in different ecological habitats in Zambia between 1980 and 1982. Wherever possible supplementary data were obtained from opportunistic collections from cattle and other hosts. Analysis of over 1000 tick collections from cattle indicated that infestation rates of the most important species, Amblyomma variegatum and Rhipicephalus appendiculatus vary in different ecological habitats: (i) In Western Province, infestations are much lower than elsewhere; (ii) in Central and Southern Provinces, moderate to high infestations occur; and (iii) in Eastern Province, R. appendiculatus numbers are generally low and A. variegatum numbers are moderate. These two species, however, have similar life cycles throughout their range with one generation per year. Larvae occur mainly from March to May, nymphae from May to September, and adults of A. variegatum from October to December and of R. appendiculatus from December to April. Boophilus decoloratus appears to have two to four generations per year but is uncommon during the rainy season. In some areas in central Zambia Rhipicephalus compositus adults are seasonally common in September-October whereas Rhipicephalus evertsi is more or less ubiquitous. Low to moderate infestations of Hyalomma truncatum and Hyalomma rufipes occur in most areas. At least 14 other less common or rare species of Rhipicephalus, Amblyomma, Haemaphysalis and Ixodes were taken infrequently from cattle. These and other host-specific species were also collected from dogs, sheep, various wildlife hosts and the environment. Infestation rates, seasonality and host-relationships of tick species are discussed in relation to their ecology. Relevant biosystematic and disease relationships are reviewed briefly. The baseline data derived from this study are adequate for integrated analysis with those from other ecological and economic investigations to formulate tick control strategies.

Animals

Enterocolitis caused by Ehrlichia sp. in the horse (Potomac horse fever).

Potomac horse fever was reproduced in 15 ponies by transfusion of whole blood originally from two natural cases and subsequently from ponies infected by the transfusions. Incubation periods varied from 9 to 15 days. Affected ponies developed varying degrees of fever, diarrhea, anorexia, depression, and leukopenia. Eleven affected ponies were killed, three died in the acute phase of the disease, and one did not show clinical signs. The most consistent post-mortem findings were fluid contents in the cecum and large colon, and areas of hyperemia (of inconstant degree and distribution) in mucosae of both small and large intestines. Multifocal areas of necrosis occurred in mucous membranes. Ehrlichial organisms were most common in the cytoplasm of epithelial cells, macrophages, and mast cells of the large colon.

Animals